At his family's summer cottage near Lake Erie in Ohio, he learned to sail a 14-foot sloop by himself.
He resigned his commission with the Navy in 1946 to join the Academy's faculty as a professor and became chairman of the First Class Committee of the Marine Engineering department.
After retiring from the Naval Academy in 1967, Gillmer continued living in Annapolis, where he pursued a career as the architect of sailing vessels and an author on the subject.
[3] The Navy hired Gillmer and Franzen to evaluate the condition of the USS Constitution prior to the vessel's restoration in 1997.
[1] The Allied Seawind Ketch, designed by Gillmer in 1962, was the first fiberglass-hulled yacht to circumnavigate the Earth.